Omar starts counting at 43, and he counts by threes. If 43 is the 1st number that Omar counts. what is the 13th number that he counts?
Explanation: What is the first number that he counts? $43$ What is the second number that he counts? $\begin{align*}&43 + 3 \\ &= 46\end{align*}$ What is the third number that he counts? $\begin{align*}&43 + 3 + 3 \\ &= 43 + (2 \times 3) \\ &= 49\end{align*}$ What is the 13th number that he counts? $\begin{align*}&43 + (12\times3) \\ &= 43 + 36 \\ &= 79\end{align*}$